RELATION OF DENSIFICATION TO PERFORMANCE OF SMALL-SCALE ASPHALTIC CONCRETE TEST SECTIONS
PERFORMANCE OF SMALL-SCALE ROAD TEST SECTIONS CONTAINING DENSE-GRADED ASPHALTIC CONCRETE HAS SHOWN THE EFFECT OF SEVERAL VARIABLES IN MIX DESIGN ON RESISTANCE TO PAVEMENT CRACKING, DISPLACEMENT AND FLUSHING. CORE SAMPLES REMOVED FROM THE SECTIONS AFTER 15 AND 43 MONTHS SERVICE REVEAL THE CONSIDERABLE DENSIFICATION THAT TOOK PLACE UNDER TRAFFIC WHILE THE PAVEMENT WAS STILL RELATIVELY NEW. SUBSTANIALLY ALL DENSIFICATION OCCURRED DURING THE FIRST 15 MONTHS. THE AMOUNT OF DENSIFICATION DURING THIS PERIOD IS SHOWN TO BE RELATED TO THE POTENTIAL DENSIFICATION, OR THE CHANGE IN AGGREGATE VOIDS THAT CAN OCCUR BEFORE THE THEORETICAL ZERO - AIR - VOIDS CONTENT IS REACHED. LEAN MIXES, WITH A HIGH POTENTIAL CHANGE, SHOW AN AVERAGE REDUCTION OF 8.0 PERCENT, WHEREAS RICH MIXES PRODUCE ONLY A 4.0 PERCENT CHANGE. DENSIFICATION OF THE PAVEMENT TENDS TO CONTINUE UNTIL THE AGGREGATE VOIDS ARE WITHIN APPROXIMATELY 3.6 PERCENT OF THE THEORETICAL ULTIMATE CONTENT FOR MIXES OF THIS TYPE. PERFORMANCE RATINGS FROM "PLASTIC" TO "BRITTLE" SHOW THE STRONG INFLUENCE OF ASPHALT CONTENT ON PERFORMANCE. LEAN MIXES IN THESE TESTS ARE PREDOMINANTLY SATISFACTORY, THEIR ASPHALT CONTENTS BEGIN BELOW THE AMOUNT NECESSARY TO FILL THE VOID SPACE WHEN THE AGGREGATE ACHIEVES ITS MAXIMUM DENSITY. WHEN THIS LIMITING SPACE IS OVERFILLED, THE MIX BECOMES SUSCEPTIBLE TO PLASTIC DEFORMATION AND FLUSHING. LIMITING ASPHALT CONTENTS OF 4.1 PERCENT TO 4.5 PERCENT (BY WEIGHT) CORRESPOND TO AGGREGATE VOIDS VALUES OF LESS THAN 14 PERCENT ( BY VOLUME) WHICH HAVE BEEN MEASURED IN THE PAVEMENT. THESE FINDINGS SHOULD AID IN DESCRIBING THE CHANGES THAT CAN BE EXPECTED IN SERVICE. THEY ALSO PROVIDE INFORMATION RELATING TO THE IMPORTANT FACTORS AFFECTING SATISFACTORY DESIGN. /AUTHOR/
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Supplemental Notes:
- No 234, pp 1-11, 10 FIG, 9 TAB, 6 REF, 2 APP Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Metcalf, C T
- Publication Date: 1959
Media Info
- Media Type: Digital/other
- Pagination: 11p
- Monograph Title: Performance and tests of asphaltic concrete
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Serial:
- Highway Research Board Bulletin
- Issue Number: 234
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Aggregates; Asphalt concrete; Asphalt content; Brittleness; Core samples; Densification; Dislocation (Geology); Flushing; Mix design; Pavement cracking; Plastic deformation; Plasticity; Test sections
- Old TRIS Terms: Cores; Zero air voids
- Subject Areas: Geotechnology; Highways; Maintenance and Preservation; Materials;
Filing Info
- Accession Number: 00211324
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Sep 9 1994 12:00AM